Precast concrete building construction

ABSTRACT

A building construction utilizing precast concrete building units which are positioned side-by-side and end-to-end as well as stacked to form a multistory structure; the units being secured together by tendons freely threaded through horizontal and vertical chases provided in the building units, placed under tension and anchored at their extremities. The building units may also include precast beams containing longitudinal catenary tendons anchored at the end extremities of each building unit, the units being bolted in end-to-end relation.

BACKGROUND OF THE INVENTION

Heretofore it has been the practice to embed steel reinforcing inconcrete and establish an intimate bond between the reinforcing andconcrete throughout the entire surface of the reinforcing. This practicehas been followed in the techniques of pretensioning and posttensioningof concrete. In the pretensioning technique, the reinforcing tendons areheld in tension while the concrete is poured around the reinforcing. Inthe posttensioning technique, the reinforcing tendons are jacketed insleeves large enough to permit sliding movement of the tendons. Then,after the concrete is set, the tendons are tensioned, grouting is forcedbetween the tendons and the sleeves so that the grouting is bonded tothe tendons and the tendons are anchored at their extremities.

In all cases, there is a continuous intimate bond between thereinforcing or tendon and the concrete or grouting. If the concrete orgrouting cracks, localized stress is applied to the reinforcing ortendon; that is, the reinforcing or tendon is stressed over the width ofthe crack (plus some relatively small bond length at each side of thecrack). As a result, the crack need only widen a small amount to stretchthe short length of the reinforcing or tendon beyond the yield point ofthe steel. If the force which caused the crack is relieved, thereinforcing or tendon does not recover, and the reinforcing or tendonexerts at least a local force tending to widen the crack.

Should the force which creates the crack or a later force be ofsufficient magnitude, the crack may widen sufficiently that thelocalized stress in the reinforcing or tendon exceeds ultimate strengthof the steel and a rupture occurs.

This problem is fully recognized so that in designing a concretestructure using ordinary reinforcing or tendon reinforcing, care istaken that the expected loads will be insufficient to produce thecracks. This, of course, materially increases the cost of construction,especially if the designer must consider gross overloads such asproduced, for example, by earthquakes or falling aircraft.

SUMMARY OF THE INVENTION

The present invention is directed to a solution of the problem andinvolves other advantages as summarized in the following objects:

First, to provide a multistory building construction which utilizesprecast building units arranged in end-to-end and side-by-side relationas well as stacked, which are connected by horizontal and verticaltendons slidably received in passageways and anchored only at theirends. As a result, the tendons are free to distribute throughout theirlength the force resulting from any change due to a crack or series ofcracks. Thus, a crack of a width sufficient to fail a bonded tendoncauses only minor stress change throughout the length of the unbondedtendon.

Second, to provide a multistory building structure as indicated in thepreceding object which is portable; that is the building structure maybe so arranged that the horizontal and vertical tendons may be removedand the building units separated for removal to another site,reassembled and reconnected by tension elements.

Third, to provide a building structure of the type indicated in thepreceding objects wherein the precast building units may includelongitudinally extending beams containing tendons disposed in catenarylike contour, anchored at the ends of the building units and free toslide therebetween, said units being bolted end-to-end.

Fourth, to provide a building structure in which the building units maybe portions of dwelling assemblies as exemplified in my copendingapplication, Ser. No. 662,602, filed Aug. 23, 1967, for BUILDINGSTRUCTURE AND MEANS AND METHOD OF ITS MANUFACTURE, and in my copendingapplication, Ser. No. 817,372, filed Apr. 18, 1969, for BUILDINGASSEMBLY AND METHOD, modified so as to be joined in the manner set forthin the other objects presented herein.

Fifth, to provide a building structure which may utilize novel buildingunits especially adapted to produce a multideck parking structure.

Sixth, to provide a building structure wherein precast concrete buildingunits involving a first set of slabs having marginal beams, a second setof slabs which further includes legs at the corners thereof and a thirdset of beam structures having a leg at each end thereof, the second setof slabs forming decks vertically spaced by said corner legs, the thirdset of slabs forming vehicle passageways between their end legs, and thefirst set of slabs forming decking bridging between said third set ofslabs.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view, showing a deck of the building construction asadapted for use as a multistory parking structure.

FIG. 2 is an enlarged fragmentary sectional view, taken in part through2--2 of FIG. 1 rotated 90°, the view, illustrating a two-story parkingstructure.

FIG. 3 is a further enlarged fragmentary sectional view, taken through3--3 of FIG. 2, portions being shown in plan.

FIG. 4 is an enlarged sectional view, taken through 4--4 of FIG. 2.

FIG. 5 is another sectional view, taken through 5--5 of FIG. 2.

FIG. 6 is a fragmentary elevational view, taken from 6--6 of FIG. 2.

FIG. 7 is an enlarged fragmentary sectional view, taken through 7--7 ofFIG. 1.

FIG. 8 is a fragmentary plan view of the portion of the buildingstructure shown in FIG. 7.

FIG. 9 is an enlarged fragmentary sectional view, taken through 9--9 ofFIG. 1.

FIG. 10 is a side view of one of the anchor plates.

FIG. 11 is a fragmentary perspective view, showing one of the buildingunits used in the building construction.

FIG. 12 is a fragmentary perspective view, showing another of thebuilding units.

FIG. 13 is a fragmentary sectional view, showing another of the buildingunits.

FIG. 14 is a fragmentary perspective view, showing a supporting leg anda portion of the foundation as well as a vertical tendon, the leg beingseparated from the foundation to illustrate the construction.

FIG. 15 is an enlarged fragmentary sectional view, taken through 15--15of FIG. 2.

FIG. 16 is an enlarged fragmentary sectional view, taken through 16--16of FIG. 2.

FIG. 17 is an enlarged fragmentary sectional view, taken through 17--17of FIG. 2.

The building construction illustrated is a multilevel parking garage,and is constructed principally by the assembly of three sets of buildingunits. The first set of building units, designated 1, includes anelongated rectangular slab or deck member 2, formed of reinforcedconcrete. The slab may also be termed a floor-ceiling slab, as it formsthe ceiling of the level below and the floor of the level above.Depending from the slab, along the longer margins thereof, is pair oflongitudinal beams 3. Transverse beams 4 are provided at the ends of theslab. Extending downwardly from the beams, at the corners of the slab,are legs 5.

The slab is provided with a set of transverse tendon passages 6. Thelegs are provided with vertical tendon passages 7. The longitudinalbeams 3 are provided with tendon passages 8.

Several tendon passages may be provided in each beam and may merge attheir central portions. The passages are curved, essentially in catenaryprofile. Each passage 8 receives a tendon 9, in the form of a steelcable, which extends through anchor plates 10 set in the ends of thelongitudinal beams. The anchor plates are provided with tapered openingswhich receive anchor wedges 11 that grip the ends of the tendons.

The passages 8 may be formed in several ways, such as by a sleeve orliner cast in place, or by a rod of elastomeric material capable ofbeing extracted after the concrete has been cast and set; or, the tendonitself may be coated with a lubricant, or encased in a sleeve.Regardless of the method employed, the tendon remains slidable in thepassage so that the tendon may be post-tensioned by use of conventionalpulling tools applied to the exposed extremities of the tendons. Later,the tendons are cut so that grout 12 may fill the recess in which theanchor plate is located.

In order to handle the building unit, each anchor plate may be providedwith a lifting boss 13, which may be grasped by a suitable liftingfitting, or may be internally screwthreaded to receive a lifting bolt.Alternatively, before the grout is applied, and the ends of the tendonstrimmed, the protruding ends may receive lifting plates 14, held inplace by removable clamping collars 15, all as indicated in FIG. 16.

Each of the second set of building units, designated 16, includes a beam17, similar in depth but of greater width than the longitudinal beams ofa first building unit. Each beam 17 is provided with longitudinal tendonpassages, tendons and anchor plates as described in connection with thelongitudinal beams 3. Each beam 17 is provided with end legs 18, similarto the corner legs 5, but having approximately twice the cross section.Also, each beam 17 is provided with side notches 19, intended toaccommodate the ends of third building units 20. Each building unit 20includes a slab 2, corresponding to the first building unit, as well aslongitudinal beams 3; that is, the transverse end beams 4 and cornerlegs 5 are omitted. Also, the ends of the longitudinal beams arenotched, as indicated by 21, in order to fit the notches 19 of thebuilding unit 16.

The three sets of building units are assembled by placing members of thefirst set of building units in end-to-end and side-by-side relation. Itis impractical to make the building units 1 of sufficient width toprovide space for vehicles between the corner legs at each end. However,the length of each building unit 1 is sufficient to accommodate two rowsof parked cars and a passageway therebetween. In order to providepassageways parallel to the longitudinal axes of the building units 1,the second building units 16 are placed in lateral alignment with theadjacent ends of selected building units 1, and the building units 20are placed between the beams 17 of the building units 16 and suitablysecured thereto, thereby forming a deck which is a continuation of thedeck formed by the slabs 2 of the first building units, as shown inFIGS. 1, 2 and 3.

As shown in FIG. 15, the first building units are secured in end-to-endrelation by tie bolts 22, which extend through openings 23 provided inthe end beams 4. The tie bolts receive load distributing flanges 24.Before applying nuts to the ends of the tie bolts 22, grout 25 is forcedin the space between the ends of adjacent units. It is preferred toprovide such grout space rather than placing the building units inabutting relation as such spacing compensates for tolerance variations.

The building units 1 as well as the building units 20 are placed inside-by-side relationship in such a manner that their transverse tendonpassages 6 are placed in alignment. The passages 6 may be circular, butto provide tolerance compensation, they may be oval or rectangular. Eachaligned row of passages 6 receives a transverse tendon 27, which extendscontinuously from one outside edge to the opposite outside edge of thebuilding structure. The building units forming such edges are providedwith exposed metal channel members 28 bonded to the concrete as well assecured by suitable reinforcing, now shown. Each end channel isperforated to receive an end of the corresponding tendon. An anchorplate 29, perforated to receive the corresponding tendon, overlies theend channel 28. Mounted on each anchor plate or arranged to bearthereagainst is a wedge collar 30, which receives a set of conicalwedges 31 adapted to grip and hold the tendon under tension.

As is the case between the ends of the building units, the sides thereofare not placed in mutual contacting relation, but space is providedtherebetween to compensate for tolerance variations. Such spaces alsoaid in insertion or threading of the tendons 27 into the passages 6.For, in the case of partial misalignment, the end of the tendon may beguided into alignment with a succeeding passage. After the tendons 27have been inserted, and before tension is applied, grout 32 is forcedinto the spaces between the sides of the building units. Temporary formsmay be inserted upwardly between adjacent longitudinal beams 3 so as toretain the grout 32 in the space provided. It should be noted that thetendons 27 are thoroughly greased or otherwise coated so that any bondbetween the tendons 27 and the grout is minimized.

It should be further noted that the grout 25 and 12 preferably containsan expansive cement, such as the cement disclosed in U.S. Pat. Nos.3,215,701 and 3,303,037. The grout mixture is compounded so that itswells slightly or at least compensates for any shrinkage that wouldotherwise occur so that on tensioning the tendons 27, there is nosignificant reduction in the overall distance between the extremebuilding units.

Each anchor plate 29 may also serve to support in part a fence wall unit33, each fence wall unit consisting essentially of a rectangularconcrete slab having sockets 34 to clear the wedge collars 30, and alsoprovided with mounting bolts 35 which are received in slots provided inupper portions of the anchor pates 29, which portions project above theslab 2. At the end extremities of the building units forming the ends ofthe building, mounting plates identical to the anchor plates 29 may beused and may be bolted to the end channel members 28, as indicated inFIG. 9.

The building units legs 5 and 18 of the lower or first level of buildingunits rest on appropriate foundation piers 36, indicated in FIG. 14.Vertical tendons 37, having conventional fixed anchorages, are securedin the foundation piers 36 and extend upwardly therefrom. The verticaltendons 37 are anchored at the time the foundation is poured, and areinitially formed in coils until assembly of the building construction isundertaken. The building units 1 and 16 are poised above the foundationpiers and the vertical tendons are threaded therethrough; that is, theend legs 18 and corner legs 5 are threaded downward on the verticaltendons, the tendons being received in the vertical tendon passages 7.After the building units have been assembled, anchor plates 38 arefitted over the protruding upper ends of the vertical tendons andappropriate wedge collars 39 and wedges 40 are applied, and the tendonsare tensioned in a conventional manner. It is preferred, of course, toplace the anchor plates 38, wedge collars 39 and wedges 40 below theupper surface of the upper deck of the structure so that the upper deckis free for use for parking purposes.

The parking structure includes appropriately located ramps 41 which maybe formed of modifications of the building units described, or may beconventional in construction. Also, suitable stairways 42 and elevatorshafts 43 are provided.

It should be noted that each of the building units contain conventionalreinforcing, not shown, in addition to the tendon reinforcing described.Also, if desired, the building units may contain expansive cementcapable of stressing the reinforcing, or to compensate for shrinkage, orconventional cement may be used. While use in the individual units ofreinforcing bonded to the concrete does create a localized stresscondition in the reinforcing, the problem is not as severe as would bethe case with the building as a whole.

It will also be noted that where the ramps 41 would interfere, thetendons 27 terminate at the ramps.

While a two story parking structure is indicated, the structure may beextended to greater height.

Should it be desired to do so, the building construction may bedisassembled. That is, the tendons 27 may be removed as well as thebolts 22, and the top anchors 39. Then, the building units may beremoved, those units having legs being raised from the tendons 37. Thegrout 25 and 32 is first removed, or, if it is intended to provide forlater disassembly, the contacting surfaces of the building units areprovided with a suitable parting agent; or, a non-adhering material issubstituted for the grout. In this regard, it should be noted that thegrout is maintained under compression so that there is no need for abond with the building units.

A known property of conventional concrete has been that if a concreteslab is sufficiently compressed in two directions within the planedefined by the slab, the slab becomes waterproof; that is, water doesnot penetrate from one surface through the slab to the opposite surface.The required compressive force has been determined to be about 300 psiin each direction. Such compression has been attained by sets of tendonsextending in each direction, which have been post-tensioned. Ifexpansive cement, such as that disclosed in U.S. Pat. Nos. 3,215,701 and3,303,037, is used, part of such compression is attained by theinteraction of the reinforcing as more fully disclosed in theaforementioned Pat. application, Ser. No. 662,602. In this case, lesssupplementary posttensioning force, for example, is required in order toattain the waterproof condition.

It has been accepted that in order to attain such waterproof conditionthe compression loads must be applied simultaneously or nearly so andsoon after the concrete has attained proper strength.

It has been found in the course of developing the present invention,that the compression loads need not be applied as nearly simultaneouslyas possible or as soon as possible after casting. Instead, it has beenfound that the longitudinal tendons 9 in each building unit may beposttensioned at any convenient time; further, the building units may bestored for a long period before being assembled into the buildingstructure and subjected to the transverse compression force exerted bythe tendons 27 and when finally compressed in the order of 300 psi inthe two axes, the slab becomes watertight.

Also previously it has been considered essential that the compressiveforces be confined to a single monolithic unit; whereas, it has beenfound that a large number of slabs placed side-by-side may becompressively stressed by a series of tendons threaded therethrough andbe rendered watertight.

With regard to the grout, if this includes a conventional portlandcement base with or without expansible ingredients, it has been foundthat if compressed in the order of 300 psi in a single transverse axisbetween the ends or the sides of the slabs, it as well as the interfacesbetween the grout and the slabs becomes watertight.

While particular embodiments of this invention have been shown anddescribed, it is not intended to limit the same to the details of theconstructions set forth, but instead, the invention embraces suchchanges, modifications and equivalents of the various parts and theirrelationships as come within the purview of the appended claims.

I claim:
 1. A multiple story garage structure, comprising:a. a first setof precast concrete building units, each unit thereof including anelongated rectangular slab and legs at the ends thereof, the slabs.Iadd.having substantially continuous upper and lower surfaces exceptfor vertical tendon passages at said legs and .Iaddend.being arranged.Iadd.coplanar .Iaddend.in side-by-side and end-to-end relation and thelegs disposed in rows under the ends of the slabs, the rows of legsdefining therebetween rows of parking spaces adjacent the legs andaccess lanes between the parking spaces; b. a second set of precastconcrete building units, each unit of the second set including a beamand a leg at each end thereof, the members of the second set of buildingunits being disposed in longitudinal alignment with the rows of legs ofthe first set at the ends thereof to define transversely extendingcorridors connecting the access lanes; c. a third set of precastconcrete building units, each unit of the third set including a slab andat least one beam thereunder, the ends of the members of the third setof building units resting on the beams of the second set of buildingunits and continuing in .Iadd.coplanar .Iaddend.side-by-side andend-to-end relation from the slabs of the first set of building units;d. and means securing the sets of building units in their assembledrelation.
 2. A building construction, as defined in claim 1, wherein:a.said building units are adapted to be stacked to form a multideckstructure; b. said legs are provided with vertical tendon guidewaysadapted to be aligned when said building units are stacked; c. and saidsecuring means includes .Iadd.steel cable .Iaddend.vertical tendonsslidably received in said aligned vertical guideways, and anchor meansare provided at the extremities of said tendons to hold said verticaltendons under tension, thereby to exert a compressive force between thevertically stacked building units, said vertical tendons being freelymovable in their respective passageways between their respective anchorswhereby tension loads thereon are uniformly distributed along the lengthof each vertical tendon.
 3. A building construction, as defined in claim1, wherein:a. each slab defines a plurality of horizontal tendonguideways, disposed .Iadd.between their upper and lower surfaces and.Iaddend.in alignment with guideways of adjacent slabs, when the slabsare assembled in side-by-side relation; b. and said securing meansincludes .Iadd.steel cable .Iaddend.tendons slidably received in theguideways of a plurality of slabs, and anchors at the remote ends of thetendons to hold said tendons under tension thereby to exert acompressive force between slabs located between said anchors, saidtendons being freely movable in said guideways between said anchorswhereby tension loads are uniformly distributed along the length of eachtendon.
 4. A building construction, as defined in claim 3, wherein:a.the slabs of said building units are initially disposed in spacedrelation; b. grout including expansive cement occupies said spaces toexert an expansive force between said slabs; c. and said tendons exert acompressive force on the grout compensating for the expansive force ofsaid grout.
 5. A horizontal multiple deck construction, comprising:a. aset of elongated concrete slabs for each deck arranged in coplanarrelation with their side edges in contiguous relation to form aplurality of continuous junctures between their side edges; b..Iadd.longitudinally extending .Iaddend.deflection resisting beamsintegral with corresponding slabs .[.;.]..Iadd., the slabs, except forsaid longitudinal beams defining between their ends essentially parallelupper and lower surfaces; .Iaddend. c. integral legs at the ends of thebeams for supporting each deck above the deck below; d. each set ofslabs having a plurality of horizontal transversely extending parallelguideways disposed .Iadd.in a zone between their upper and lowersurfaces and .Iaddend.in alignment across the junctures and through aplurality of slabs; e. a plurality of continuous slab connecting.Iadd.steel cable .Iaddend.flexible tendons, slidable in and coextensivewith the guideways in each deck; f. anchoring means secured to the endsof the tendons of each deck to maintain predetermined uniformity ofdistributed tension loads throughout the lengths of the tendons therebyto maintain corresponding compression loads .Iadd.in and parallel to thecommon zone of the tendons between the upper and lower surfaces of theslabs and .Iaddend.distributed throughout the slabs disposed between theanchors as well as the junctures between contiguous slabs, the tensionloads being of sufficient magnitude to secure the slabs against relativemovement at their junctures, thereby to cause the slabs to resistdeflecting forces as a unit; g. the legs extending between the decksbeing disposed in vertically aligned groups and each leg forming ajuncture with a slab of the deck below; h. a pier below the lowermostleg of each group and forming a horizontal juncture therewith; i. eachgroup of legs, the corresponding ends of the beams and the slabstherebetween having vertical guideways extending from the pierstherethrough; j. flexible tendons extending through the verticalguideways; k. and anchoring means in said piers and bearing against theslabs of the top deck secured to the vertical tendons to maintain apredetermined uniformity distributed tension loads throughout thelengths of the vertical tendons thereby to maintain compression loadsdistributed throughout the legs, beam ends and slabs disposed betweenthe anchors as well as the horizontal junctures therebetween to causethe decks to resist deflection forces as a unit.
 6. A multiple storybuilding construction, comprising:a. at least four building unitsforming a lower story; each unit including a horizontal rectangularconcrete slab .Iadd.defining upper and lower surfaces and.Iaddend.having a major longitudinal and a minor lateraldimension.Iadd., .Iaddend.underlying supporting beams extendinglongitudinally of the slabs between the ends thereof and spaced verticalconcrete legs fixed to the ends of the slabs; b. the four units beingassembled with the slabs in a common horizontal plane and with the endsof the slabs in abutting relation on .Iadd.at least a .Iaddend.firstvertical plane.[.s.]., the adjacent longitudinal edges of adjacent slabslikewise being in abutting relation on .Iadd.at least a .Iaddend.secondvertical plane.[.s.]. at right angles to the first named plane.[.s.].;c. foundation means serving to engage and support the lower ends of thevertical legs; d. at least four building units assembled upon the firstfour units and forming a second story; e. the units of the second storylikewise each including a horizontal rectangular concrete slab.Iadd.defining upper and lower surfaces and .Iaddend.having a majorlongitudinal and a minor lateral dimension.Iadd., .Iaddend.underlyingsupporting beams extending longitudinally of the slabs between the endsthereof.Iadd., .Iaddend.and spaced vertical concrete legs fixed to theend portions of the slabs; f. the four units of the second story beingassembled with their slabs in a common horizontal plane and with theadjacent ends of the slabs in abutting relation on said first verticalplane.[.s.]. and the longitudinal edges of adjacent slabs being inabutting relation on said second vertical plane; g. the vertical legsfor the upper story having their lower ends seated upon end portions ofan underlying slab and in vertical alignment with legs for the lowerstory; h. the space between vertical legs of a story as measuredlongitudinally of the units being substantially unobstructed to formfree corridors; i. the legs for adjacent ends of units for the secondstory being disposed adjacent and on opposite sides of a correspondingfirst plane; j. the slabs of the units forming both the lower and upperstories having aligned horizontal tendon accommodating guideways.Iadd.occupying a common zone between the upper and lower surfaces ofthe slabs and .Iaddend.extending laterally through the same from oneremote longitudinal side edge of a slab to the remote other side edge;k. the end portion of each slab of the units forming both the lower andupper stories having a vertical tendon accommodating guideway extendingthrough the same and through a corresponding vertical leg; l. thevertical guideways of the units forming the upper floor being alignedwith the vertical guideways of the units forming the lower story; m.tensioned horizontal .Iadd.steel cable .Iaddend.tendons extendingthrough the horizontal guideways of the slabs and tendon anchors at theremote side edges of the slabs thereby serving to apply forces incompression to the slabs .Iadd.centered in the common zone of thehorizontal guideways thereby .Iaddend.causing mutual engagement of theirintermediate longitudinal edges; n. tensioned .Iadd.steel cable.Iaddend.tendons extending through the aligned vertical guideways andtendon anchors in the foundation means and upper story serving to applyforces in compression to the vertical legs and to the correspondingportions of the slabs engaged thereby; o. the portions of the horizontaltendons intermediate their extremities being free of force transmittingattachment with the slabs through which they extend; p. the portions ofthe vertical tendons intermediate the foundation means and their upperextremities being free of force transmitting attachment with the legsand slabs through which they extend; q. and means securing adjacent endsof the slabs together.
 7. A multiple deck structure, comprising:a. a setof elongated concrete modules, each module including a horizontallyextending slab .Iadd.defining upper and lower surfaces.Iaddend., atleast one beam extending between the ends of the slab, at least onevertically extending leg adjacent each end of the beam; b. each modulehaving a vertical tendon guideway extending continuously through eachleg, beam and slab, the modules being stacked with their respectivevertical guideways in vertical alignment, and the modules having areasof mutual engagement between the extremities of their legs and the slabsof vertically adjacent modules; c. continuous .Iadd.flexible steel cable.Iaddend.tendons slidable in the aligned guideways; d. and tendonanchoring means at the upper and lower extremities of the guidewaysbearing against the modules for applying vertical tension to the tendonsand vertical compression loads to the extremities of the slabs and beamsand longitudinally of the legs as well as the areas of mutualengagement, thereby securing said areas against relative displacementand increasing resistance of the slabs, beams and legs to bending loads.8. A multiple deck structure, as defined in claim 7, wherein:a. thelower tendon anchoring means includes foundation piers disposed underthe legs of the lowermost modules; b. and the tendons for each stack ofmodules are adapted to be threaded through the guideways in sequence asthe modules are placed in stacked relation.
 9. A horizontal deckconstruction, comprising:a. a set of elongated concrete slabs.Iadd.defining essentially parallel upper and lower surfaces and.Iaddend.arranged in coplanar relation with their side edges incontiguous relation to form a plurality of junctures coextensive withthe side edges; b. the slabs having a plurality of parallel, alignedtendon guideways .Iadd.disposed in a common zone between the upper andlower surfaces of the slabs and .Iaddend.extending continuously throughthe set of slabs transverse to said junctures; c. a plurality ofcontinuous slab connecting .Iadd.steel cable .Iaddend.flexible tendons.Iadd.in the common zone of the guideways, and .Iaddend.slidable in andcoextensive with the guideways; d. anchoring means engaging the tendonsand fixed to the slabs at the ends of the guideways the anchoring meansmaintaining predetermined tension loads on the tendons and correspondingcompression loads in the slabs, including the junctures therebetween.Iadd.also centered in the common zone of the guideways and saidcompression loads being .Iaddend.of sufficient magnitude to secure theslabs against relative movement at their junctures thereby to cause theslabs to resist deflection forces as a unit; e. and a set of deflectionresisting slab supporting beams underlying the slabs and extendingparallel to the junctures, the beams being in rigid relation to theslabs and cooperating therewith to support loads as a unit.
 10. Aconstruction, as defined in claim 9, wherein:a. said anchoring means areremovable from the tendons and the tendons are removable from the slabsto permit disassembly of the slabs thereby to permit removal to anothersite for reassembly.
 11. A construction, as defined in claim 9,wherein:a. supporting legs extend vertically from the ends of each beamto form with the set of beams and corresponding set of slabs a set ofcoplanar building units; b. and the sets of building units are stackedvertically to form a multiple story structure.
 12. A multiple storystructure, as defined in claim 11, wherein:a. a first set of tendonanchoring means underlie the supporting legs of the lowermost set ofbuilding units; b. junctures are formed between the members of eachstack of building units; c. the supporting legs, beams and slabs of eachstack of building units have vertical tendon guideways extendingcontinuously between the tendon anchoring means and the top of themultiple story structure; d. a plurality of vertical tendons are securedto the first set of tendon anchoring means and are slidable in thevertical guideways; e. and a second set of tendon anchoring means engagethe upper ends of the tendons and are fixed to the top of the multiplestory structure to maintain vertical tension loads on the tendons andcorresponding vertical compression loads on the members of each stack ofbuilding units as well as the junctures therebetween to secure themembers against relative movement at their junctures thereby to causethe members of each stack of building units to resist deflection forcesas a unit.
 13. A construction, as defined in claim 12, wherein:a. theanchoring means for the slab connecting tendons are removable therefrom,and the tendons are removable from the slabs to permit disassembly; b.at least the second act of anchoring means for the vertical tendons areremovable therefrom to permit disassembly of each stack of buildingunits, whereby the building units may be removed to another site forreassembly. .Iadd.
 14. A horizontal deck construction, as defined inclaim 9, wherein: a. the side edges of the slabs are initially disposedin spaced relation; b. and grout is received in the spaces between theslabs and around the portions of the tendons traversing said spaces:.Iaddend..Iadd.
 15. A horizontal deck structure, as defined in claim 14,wherein: a. the grout includes expansive cement to exert an expansiveforce between the slabs. .Iaddend..Iadd.
 16. A slab structure,comprising: a. a plurality of elongated slab members having essentiallyplanar upper and lower surfaces and being arranged with their side edgesin side-by-side relation to form a slab set; b. means for supporting themembers of the slab set in coplanar relation; c. each slab member havinga plurality of transverse parallel coplanar tendon guideways distributedbetween said upper and lower surfaces; d. the tendon guideways of theslab members forming the slab set being in alignment between andincluding the remote slab members of the slab set; e. a plurality ofsteel cable tendons coextensive with the slab set and maintainedslidably received in the guideways; f. and anchoring means fixed to theend slab members of the slab set and engaging the tendons to apply apredetermined distributed tension force thereto throughout the slab setand a corresponding uniform transverse compression force to all the slabmembers of the slab set, the tendons remaining free to slide relative totheir guideways to maintain such uniform distribution of tension andcompression while permitting change in the dimensions of the slab setcaused by external forces. .Iaddend..Iadd.
 7. A slab structure, asdefined in claim 16, wherein:a. grout is disposed between the side edgesof the slab members of the slab set and around the portions of tendonstraversing the grout between the slab members, the tendons beingslidable with respect to the grout as well as the guideways to permitand maintain distributed tensioning of the tendons. .Iaddend. .Iadd. 18.A slab structure as defined in claim 17, wherein: a. the grout includesexpansive cement to exert an expansive force between the slab members ofthe slab set. .Iaddend. .Iadd.19. A slab structure, as defined in claim16, wherein: a. supporting cross beams underlie a selected number of theslab members of the slab sets at the ends thereof..Iaddend..Iadd.20. Aslab structure, as defined in claim 17 wherein: a. legs are provided atthe ends of each cross beam; b. and other legs are provided under theends of selected other slab members of the slab set to elevate the slabset. .Iaddend.
 21. A slab structure, as defined in claim 16, wherein: a.the slab set is provided with a plurality of underlying reinforcingbeams integral with and extending longitudinally with respect to theslab members. .Iadd.
 22. A slab structure as defined in claim 19,wherein: a. each longitudinal beam includes at least one tendonextending the length thereof, and tendon anchors at the ends thereof..Iaddend..Iadd.
 23. A slab structure as defined in claim 19, wherein: a.selected slab members include integral depending legs underlyingselected beams. .Iaddend..Iadd.
 24. A slab structure, as defined inclaim 23, wherein: a. a plurality of slab sets are stacked to form aplurality of floors; b. the depending legs of each floor are disposed invertical alignment, and include continuous vertically aligned tendonguideways extending through the legs and corresponding slab members..Iaddend.